The Siri Dictation feature that is currently exclusive to the iPhone 4S — along with Siri — can now be used on the iPhone 4, iPod touch 4G, and iPhone 3GS. Developer Eric Day has released a new jailbreak package called Siri0us, that is available via a Cydia repository, and will allow you to easily get Siri Dictation working. As you can see in the video above, Siri0us works just like Siri Dictation would on the iPhone 4S, but sadly it does have ads. This tweak uses Nuance’s technology, but it’s cool nonetheless.

Meanwhile, developers are still working to bring a Siri port to the iPhone 4, and have already come up with some pretty cool custom use cases. If you already have your iPhone 4 jailbroken this wouldn’t be a bad thing to check out.

Update: The developer has pulled the app from Cydia as he finds a new voice recognition service to do this legally.